| Mesoporous silica (mSiO》material is a new inorganic biological material withhigh specific surface area, big pore volume, controllable morphologies and sizes. Inrecent years, its applications in the ifeld of biomedical research have caused wideattention. In this thesis, mesoporous silica-coated Mn^C^(Mn304@mSi02)nanoparticles were used as the foundation for fabricating multifunctional mateirals,which have the functions of T\contrast agents, photodynamic therapy, chemotherapy,photothermal therapy and their mutual synergy, and the preliminary studies at thecellular level about the therapeutic effect of the resulting materials have beenconducted. This thesis is divided into four chapters.The ifrst chapter summarizes the development of mesoporous silica coatednanoparticles. From the earliest MFeCMS nano-spherical material with a mean size of270nm prepared by high temperature calcination (reported by Wenru Zhao and et al.)to the preparation of thickness-adjustable mSi02-coated single nanoparticle by JaeyunKim, the coating process got a good development. At the same time, this paperintroduces the pirnciple of magnetic resonance imaging (MRI)，drug transport,photodynamic therapy and the application of photothermal therapy. Finally theresearch idea of this paper is put forward.In the second chapter，we used oleylamine as the solvent to prepare uniformparticle sized and monodispersed M113O4nanoparticles by solvothermal method, andthen the surface of MnjOa was coated by an mSiO〗 layer with a thickness of20nmthrough sol-gel method. Then we introduced amine groups on the surface by thehydrolysis of3-ammonia propyltricthoxysilane (八PTES) for further covalentconjugation of photosensitizer chlorin6and biocompatible poly(ethylene glycol)(PEG), and finally we got the composite Mn304@mSi02-Ce6/PEG. Because niSiCh has large surface area and it can be used as the drug carrier, we introduced a newanticancer drug of Curcumin. The in vitro experiments show that the Mn304@mSi02-Ce6/PEG has low cytotoxicity and good magnetic resonance imaging enhancementeffect in cancer cells. It is noteworthy that the composite material has larger drugloading effect. Curcumin is a hydrophobic drug, and it is dififcult to directly enter thecancer cells, but it can be successfully delivered into the cells through the carirer Thedrug-loaded material showed obvious toxicity to HeLa cells. At the same time, underthe irradiation with632.8nm laser, Ce6can generate singlet oxygen which has strongkilling effect on HeLa cells. Therefore, Mn304@mSi02-Ce6/PEG composite materialcan be used as an effective MRI contrast agent, photodynamic therapy material, anddrug carrier. It is expected to be used in the diagnosis and treatment of cancers.In the third chapter, we prepared a new composite material Mn304@mSi02@CuS-PEG on the basis of Mn304@mSiC>2nanomaterials. At the same time, a newphotosensitizer molecule methylene blue (MB) was loaded in the cavity of mSi02. Asa good photothermal therapy reagent, CuS nanoparticles have become a researchhotspot in recent years. The composite material has good biocompatibility and lowtoxicity. Through the irradiation of980nm laser, Mn304@mSi02@CuS-PEG showedgood photothermal effect. Moreover, under the excitation of632.8nm, MB canproduce singlet oxygen. These results indicate that this multifunctional compositemateiral has the functions of MRI, photodynamic therapy and photothermal therapy,so it may be applied to the diagnosis and treatment of cancer in the future.In the fourth chapter, the results of this thesis are summarized, and they mayprovide new ideas for the preparation and applications of novel multifunctionalcomposite materials. At last, the prospect of our prepared materials in the ifeld ofbiomedical applications has also been discussed. |
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